Japanese Patent Application No. 2001-19038, filed Jan. 26, 2001, from which this application claims priority, is hereby incorporated by reference in its entirety.
The present invention relates to manufacture of a semiconductor device, and more particularly to a method of fabricating a jig for a vacuum apparatus, which is applied to prevent adhesion of deposits on interior walls of a vacuum chamber of a thin film forming apparatus.
A thin film forming process is known as one of LSI manufacturing processes (wafer processes). The thin film forming process may include a film forming method conducted by a physical vapor deposition (PVD) method such as vacuum vapor deposition and sputter vapor deposition, and a vapor phase growth technique, for example a chemical vapor deposition (CVD) method.
These thin film-forming processes are accomplished in a film growth chamber, or a vacuum chamber. When film-forming processes are repeated in a vacuum chamber, residual materials that are not exhausted may accumulate. The residual materials cause particle contamination through adhering as deposits to or peeling from an internal wall of the chamber or areas around peripheral apparatuses such as wafer stages. As a countermeasure, vacuum apparatus jigs for preventing deposits are disposed in areas of importance within the chamber, and jigs on which deposits have accumulated are replaced every fixed period with clean jigs (recycled products). By this procedure, particle generation during film growth is suppressed.
As the vacuum apparatus jigs described above, recycled products, in which metal plates such as stainless steel plates are subject to wet washing to smooth out their surfaces or to blast (horning) washing to roughen their surfaces, are conventionally used. However, the former has a flat surface and therefore has a problem that cohesive strength of deposits is weak. The latter provides great cohesive strength of deposits, but may cause particle contamination on the surfaces of their own that have been blast-treated.
In recent years, techniques such as increasing the surface area of the vacuum apparatus jig by thermal spraying are employed to improve cohesive strength of deposits. More particularly, Ti, Al or the like is thermally sprayed on surfaces of metal plates such as stainless steel plates to form jig surfaces having large surface areas to which deposits can readily adhere. However, during the film forming process, re-peeling of the thermal spray material or gas discharge therefrom takes place more than a little, which causes particle contamination and lowered vacuum level within the vacuum chamber.
The present invention has been made in view of the circumstances described above, and the present invention may provide a method of fabricating a highly reliable jig for a vacuum apparatus, which suppresses generation of particles and deterioration of the vacuum level within a vacuum chamber.
According to one aspect of the present invention, there is provided a method of fabricating a jig for a vacuum apparatus, which is provided in a vacuum chamber for conducting a film forming process to prevent deposits from adhering to the vacuum chamber, the method comprising:
a step of blasting on a base member,
a step of thermally spraying a thermal spray member on the base member, and
a step of covering a surface of the thermal spray member with an oxide film or a nitride film as an uppermost surface.
In this manner, an extremely thin oxide film or nitride film is formed as the uppermost surface, which contributes to prevention of re-peeling of thermal spray material of the thermal spray member and prevention of gas discharge. Furthermore, deposits can be removed at the same time when the oxide film or the nitride film formed as the uppermost surface is removed.
In this method, the oxide film or the nitride film may be a thin film of an atom layer level.
According to another aspect of the present invention, there is provided a method of fabricating a jig for a vacuum apparatus, which is provided in a vacuum chamber for conducting a film forming process to prevent deposits from adhering to the vacuum chamber, the method comprising:
a step of blasting a base member,
a step of coating the base member with an intermediate layer,
a step of thermally spraying a thermal spray member on the intermediate layer, and
a step of covering a surface of the thermal spray member with an oxide film or nitride film as an uppermost surface,
wherein the intermediate layer adsorbs a discharging gas component contained in the thermal spray member.
In this manner, an extremely thin oxide film or nitride film at a level of an atom layer is formed as the uppermost surface, which contributes to prevention of re-peeling of thermal spray material of the thermal spray member and prevention of gas discharge. The interposed intermediate layer adsorbs a discharging gas component, such as moisture, contained in the thermal spray member. Furthermore, deposits can be removed at the same time when the oxide film or the nitride film formed as the uppermost surface is removed.
In this method, the intermediate layer may contain zirconium or titanium as a main component.
In this method, the oxide film or the nitride film may be a thin film of an atom layer level.